KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
Anima App - Design, get feedback, convert to code, publish, iterate.
LTspice - LTspice® is a high performance SPICE simulation software, schematic capture and waveform viewer with enhancements and models for easing the simulation of analog circuits.
BuilderX - Design to code, designers and developers on one platform.
Fritzing - Fritzing is an open-source initiative to support designers, artists, researchers and hobbyists to...
Makers.so - A website builder inside Figma.